Comparison: DSL modem as bridge versus DSL modem as router with DHCP

Consider the typical hardware setup for home service:

[DSLAM]--------[DSL Modem]-----[local router]-----[PC]


From a security and performance perspective is there an advantage to
a) having a DSL modem configured as a bridge as compared having it as
an IP Router.
b) in the case that the DSL modem is an IP router is there an
advantage to having the DHCP function in the modem versus the local
router.


More specifically consider the following to configurations:

DSL Modem with IP:

[DSLAM]----TCP/IP/PPPOE/ATM/DSL-----[modem]-----
---------TCP/IP/ethernet -----[router]-----------------
----TCP/IP/ethernet-----[PC]


DSL Modem configured as bridge:

[DSLAM]----TCP/IP/PPPOE/ATM/DSL-------[modem]-----
---TCP/IP/PPPOE/ethernet---------- [router]----
---TCP/IP/ethernet-----[PC]


I once experimented with having PPP terminate inside a PC. So
hardware configuration was
[dslam]----[modem]----[pc].
I noticed that the pc performance degraded as compared to having the
pc connnected to a router. I attributed this to either the traffic
from the DSLAM or the PPP protocol was more chatty (i.e., more
packets) and therefore interrupted the pc more often.

Is there any performance gain by having PPP terminate in the DSL
modem?

In the case that the DSL modem is an IP router, is there a security
gain from having DHCP function in the local router?

wrote:
> Consider the typical hardware setup for home service:
>
> [DSLAM]--------[DSL Modem]-----[local router]-----[PC]
>
>
> From a security and performance perspective is there an advantage to
> a) having a DSL modem configured as a bridge as compared having it as
> an IP Router.
> b) in the case that the DSL modem is an IP router is there an
> advantage to having the DHCP function in the modem versus the local
> router.
>
>
> More specifically consider the following to configurations:
>
> DSL Modem with IP:
>
> [DSLAM]----TCP/IP/PPPOE/ATM/DSL-----[modem]-----
> ---------TCP/IP/ethernet -----[router]-----------------
> ----TCP/IP/ethernet-----[PC]
>
>
> DSL Modem configured as bridge:
>
> [DSLAM]----TCP/IP/PPPOE/ATM/DSL-------[modem]-----
> ---TCP/IP/PPPOE/ethernet---------- [router]----
> ---TCP/IP/ethernet-----[PC]
>
>
> I once experimented with having PPP terminate inside a PC. So
> hardware configuration was
> [dslam]----[modem]----[pc].
> I noticed that the pc performance degraded as compared to having the
> pc connnected to a router. I attributed this to either the traffic
> from the DSLAM or the PPP protocol was more chatty (i.e., more
> packets) and therefore interrupted the pc more often.
>
> Is there any performance gain by having PPP terminate in the DSL
> modem?
>
> In the case that the DSL modem is an IP router, is there a security
> gain from having DHCP function in the local router?

It would seem that [PC] is really [HP PC] for this topic to be addressed
in this newsgroup. ;>)

To answer your first question, it would be necessary to configure
computer, router and DSL modem both ways and to measure the throughput
using a fairly standard test from www.dslreports.com .

There is probably a minor improvement in security from having DHCP
managed by the local router rather than the DSL modem. This will also
make it a little more complicated to use VNC for remote computer access,
if that is a consideration.

When setting up DSL together with a wireless router, I generally have
configured the DSL modem as a bridge and let the router handle DHCP
chores... Ben Myers